Turbulence blamed for US jet crash

Doomed American Airlines flight 587 veered out of control and crashed into New York after twice hitting turbulence left by a jumbo jet, investigators said today.

The second blast of air sent it careering sideways, seconds before it slammed into Queens killing 265 people, said National Transportation Safety Board Chairwoman Marion Blakey.

The jet's black box revealed that it encountered "wake turbulence" from the Japan Airlines plane about 28 seconds before the end of the recording, and again 20 seconds later, said Ms Blakey.

The information lends weight to the theory that the Airbus A300's tail was ripped off by turbulence from the earlier plane, leaving the pilots unable to control the aircraft.

"There were no marks on the fin section or the rudder," NTSB member George Black told CNN.

"We haven't found any other evidence of any impact with any foreign object. It appears to be some sort of aerodynamic effect."

Mr Black said they were almost certain the 27-foot tail was the first part to break off the jet.

"The pilots don't have a rearview mirror. They have no idea they've lost a tail."

Former jet pilots said wake turbulance, the swirl of air behind a plane, could have struck the jet with the force of a mini tornado, causing the tail of the Airbus A300 to snap clean off.

Standard protocol says there should be at least two minutes between takeoffs but investigators said it appeared there was just 1 minute and 45 seconds between Flight 587 and the Japan Airlines jumbo jet that left ahead of it from the same runway.

They said air traffic controllers followed proper procedure, but there was a delay from the time the first plane got clearance to the time it actually took off.

The cockpit voice recorder from Flight 587's final minutes revealed two rattling noises and indicated the pilots mentioned the wake of another plane before their aircraft went down.

Ms Blakey said the pilots lost control in the final eight seconds, after the second blast of air, as the "rudder position data became unreliable."

The plane broke up and fell from the sky after the tail sheared away shortly after take-off on from Kennedy Airport on Monday.

All 260 people on board the jet died. Five people on the ground in Belle Harbour, Queens, were also killed.

American Airways is doing sample inspections of its remaining 34 Airbus A300s to ensure there are no problems with other tail assemblies US authorities are expected to order inspections of all Airbus A300s.